PERFORMANCE OF WOVEN GEOSYNTHETIC PRODUCTS FOR STREAM BANK EROSION CONTROL: CASE STUDY

Abstract

Bank erosion causes damage to property and human habitation every year. This problem needs effective and economical solution. In Uttar Pradesh, Ratauli, Hatwa and Bokta barwar embankment were severely affected by bank erosion, a large chunk of land was disappeared over night in the flood. Using conventional methods of bank protection have proved to be highly costly proposition in respect of both capital investment and recurring maintenance and also need much time for implementation. So, instead of using other river training techniques, a new technique for protection of bank slope and reaches of river using multi filament woven geotextile has been used on the right bank of Sharda river at Ratauli and Musiana in year 2011, right bank of Ghaghara river at Hatwa and right bank of Rapti river at Bokta barwar bund. Woven geotextile normally filled with sand or river bed material, having volume of were used in this protection work. Flood protection project was divided into two part. Three rows of porcupine in 150m length at center to center 500m and three rows of porcupine in 21m length at center to center 60m distance across the river width in 1550m length of river with 8m wide launching apron of geotextile bags. These bags were also placed on the slope of bed. The woven geotextile bag used in this project made from polypropylene having warp tensile strength of 55kN/m. After passing many floods, it has been noticed that the flood protection work successfully restored the eroded bank and 130 to 140 Hectare of valuable agricultural land was reclaimed in 5 years. Also, Sharda river has been deflected away from the erosion affected reach. Instead of using RCC or Masonry to protect bank of river Ghaghara, multifilament woven geotextile bags of having volume of 0.15m3 were used. Intermittent bank protection work can be seen of different length. Bank protection work consists of 3 rows of porcupine in 21m length of center to center 60m distance along with river bank with 8m wide launching apron. Material of woven geotextile is polypropylene having warp tensile strength of 55kN/m. After 4 years, it can be seen in field that protection work successfully deflects the river away from the erosion affected bank and also induced deposition of silt over a wider area of more than 200 to 300 hectare from which some part could be now used as agriculture land